Intravascular interventional procedures for providing an artificial embolism are desirable in some patients for controlling internal bleeding, preventing blood supply to tumors, or relieving pressure in the vessel wall near an aneurysm. Several approaches are proposed for providing an artificial embolism, including the use of an inflatable, detachable balloon or the injection of a coagulative substance. Another approach utilizes an occlusive wire coil and delivery system for positioning the coil in a desirable site of a blood vessel.
One wire coil and delivery system includes a flexible, coiled wire that when released from the distal end of a catheter assumes a randomly coiled, space-filling mass. The wire is released from the catheter by a pusher catheter with a closed distal end for engaging the proximal end of the coil. A problem with this system is that the wire coil is pushed toward the target embolism site and then assumes a randomly coiled configuration. As a result, the desirable position of the coil is targeted and aimed for but not positively attainable. Only after the coil has assumed a randomly coiled configuration can the coil be checked for desirable positioning via a visualization means such as fluoroscopy.
Another wire coil and delivery assembly includes embolic coils that are attached to the connector of a probe assembly by a heat releasable adhesive bond. To release an embolic coil, laser energy is transmitted through the probe for heating the connector and adhesive bond. A problem with this wire coil and delivery assembly is that it requires the use of laser energy. As a result, the assembly is relatively expensive to manufacture and make available to clinicians.
A further wire coil and delivery device includes a coil with a preprogrammed, helical configuration and a proximal eye for attaching to the distal knuckle of a release wire. To release the wire coil, the release wire knuckle is removed from the eye. A problem with this wire coil and delivery device is that inadvertent lateral movement potentially detaches the eye and knuckle. As a result, the coil is prematurely released in the vascular system of a patient at an undesirable site.
Yet a further wire coil and delivery device comprise a platinum guidewire tip attached to a stainless steel guidewire. To release the platinum guidewire tip, a positive current is applied to the stainless steel guidewire for corroding away the guidewire in the bloodstream and releasing the platinum guidewire tip. A problem with this method of detaching the guidewire tip is that it is relatively time intensive and prolongs the duration of an artificial embolization procedure.
A major problem with all of these devices and procedures is the precise positioning of the occlusion or intravascular treatment device within the vascular system of the patient. Once released, the treatment device is normally irretrievable and very difficult to reposition. What is needed is a delivery system for precise positioning and repositioning of the device once introduced into the vascular system. What is also needed is an intravascular treatment system in which the device can be retrieved and redeployed at another occlusion site should the physician so desire.